[Halon]

I have Sirius also. And I have the X-ACT receiver too. Just like you said, with the portable units, you do lose a little sound quality since your counting on the FM Modulator to send the signal from the receiver to your car stereo. But I didn't want a permanent install because I want to be able to swap it from the galant to the talon whenever i want, and to be able to bring it with when I travel. I love it. Sometimes if the frequency your using is a frequency that comes in a little through the air waves, you can hear some interference. But I just deal with it.

Also like Chris said, it comes in handy since it's portable, if I ever want to bring it into the house for a party, and play it through the home stereo. You can just sign on to their site, and listen to it through the site in your house, but my computer isn't hooked up to my home stereo so that doesn't really work out well for me. Once I get a real nice daily driver, I'll get a permanently installed one in it. And if you don't care about swapping it from one car to another, or bringing it inside, I'd get it permanently installed, becaues it'll sound better, and just look cleaner overall.